PulseIn is used to measure a series of active and idle pulses. This is commonly used in infrared receivers and low cost temperature sensors (DHT). The pulsed signal consists of timed active and idle periods. Unlike PWM, there is no set duration for active and idle pairs.
PulseIn(pin, maxlen=2, *, idle_state=False)¶
Create a PulseIn object associated with the given pin. The object acts as a read-only sequence of pulse lengths with a given max length. When it is active, new pulse lengths are added to the end of the list. When there is no more room (len() ==
maxlen) the oldest pulse length is removed to make room.
Read a short series of pulses:
import pulseio import board pulses = pulseio.PulseIn(board.D7) # Wait for an active pulse while len(pulses) == 0: pass # Pause while we do something with the pulses pulses.pause() # Print the pulses. pulses is an active pulse unless the length # reached max length and idle pulses are recorded. print(pulses) # Clear the rest pulses.clear() # Resume with an 80 microsecond active pulse pulses.resume(80)
Deinitialises the PulseIn and releases any hardware resources for reuse.
No-op used by Context Managers.
Automatically deinitializes the hardware when exiting a context. See Lifetime and ContextManagers for more info.
Pause pulse capture
Resumes pulse capture after an optional trigger pulse.
Using trigger pulse with a device that drives both high and low signals risks a short. Make sure your device is open drain (only drives low) when using a trigger pulse. You most likely added a “pull-up” resistor to your circuit to do this.
Parameters: trigger_duration (int) – trigger pulse duration in microseconds
Clears all captured pulses
Removes and returns the oldest read pulse.
The maximum length of the PulseIn. When len() is equal to maxlen, it is unclear which pulses are active and which are idle.
True when pulse capture is paused as a result of
pause()or an error during capture such as a signal that is too fast.
Returns the current pulse length
This allows you to:
pulses = pulseio.PulseIn(pin) print(len(pulses))
Returns the value at the given index or values in slice.
This allows you to:
pulses = pulseio.PulseIn(pin) print(pulses)